Research On Thermal Error Modeling Of CNC Machine Tools Based On The Theory Of Gray System

A CNC machine tool QLM27100is as the research object. The methods of the temperaturemeasuring point optimization and the thermal error modeling are based on the theory of Gray system,and the methods are improved. The main research contents are as follows:The structure features of CNC machine tool QLM27100are introduced and the heat resourcesare analyzed. The location of temperature sensors and displacement sensors fixing on the machine isdetermined, and the data of temperature and thermal error was collected.The method to optimize the temperature measuring points is combined gray correlation analysiswith fuzzy clustering analysis. The theory of gray correlation analysis is used to select sometemperature measuring points by the influence of thermal error. The selected temperature measuringpoints are clustered by fuzzy clustering analysis, and the group of optimum temperature measuringpoints is got. Finally, two different methods of temperature measuring point optimization are used onQLM27100CNC machine tool, and the two groups of optimum temperature measuring points areused to build multiple regression model. The result of comparing the precision of the two modelsshows that the method of gray correlation analysis and fuzzy clustering analysis is better.The method of thermal error modeling is used grey system model and time series analysis model.The grey system model is used to build thermal error modeling, and the residual thermal error isstudied by time series analysis model. The comprehensive model is composed of the two models. Theresult shows that the comprehensive model can effectively improves the precision of thermal errormodeling.The thermal error compensation system is introduced. The QLM27100CNC machine tool is asthe research object. The grey system and time series analysis model is verified. Based on thetemperature compensation function of SINUMERIK840D CNC system, the temperaturecompensation experiment obtains better compensation effect.